Astronauts will spend much of today getting ready for a fourth spacewalk during Discovery's mission to the International Space Station.

On Saturday, Mission Specialists Bob Curbeam and Expedition 14 Flight Engineer Sunita Williams finished rewiring the International Space Station during a 7-hour, 31-minute spacewalk.

After planned tasks had been completed smoothly and ahead of schedule, they also shook a balky solar array wing in hopes of completing its retraction. That helped gain some ground ? the wing is about 65 percent retracted, compared to less than 50 percent before the spacewalk. About 11 bays remain deployed, compared to about 17 before.

Managers decided Saturday afternoon to add that fourth spacewalk to Discovery's visit to the station. This one will be done by Curbeam, who participated in all three of the previous spacewalks, and Christer Fuglesang, a spacewalker on the first two. While Curbeam and Williams were still outside Saturday, mission managers decided to add the spacewalk, scheduled to start at 12:47 p.m. CST on Monday, and to add a day to Discovery's stay at the station.

Today the station's Canadarm2 will be moved into position to support the Monday spacewalk. Discovery's arm will be used to provide camera views. Discovery crew members will reconfigure spacesuits and transfer them to the station's Quest airlock. At 8:02 p.m., Discovery and station crews will hold a procedure review for the spacewalk.

Curbeam and Fuglesang will begin an overnight ?campout? in the airlock, its pressure reduced to 10.2 psi. The crew goes to bed at 12:17 a.m. Monday. The campout is part of a process to avoid any possibility of the two spacewalkers developing decompression sickness in the relatively low pressure of their spacesuits. The suits are pressurized to a little less than 5 psi.

In other activities, transfer of equipment and supplies between the spacecraft is about 70 percent complete. Crewmembers and flight controllers believe it should be mostly finished after today's work.

Shuttle crewmembers Commander Mark Polansky, Pilot Bill Oefelein and Mission Specialists Nicholas Patrick, Curbeam, Fuglesang, Joan Higginbotham and Thomas Reiter, were awakened at 8:17 a.m. CST to the ?Beautiful Blue Danube" performed by the Vienna Philharmonic Orchestra. The music was for Fuglesang. The next STS-116 status report will be issued Sunday evening, or earlier if events warrant.

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